Genetic Susceptibility to Diabetic Nephropathy is Related to Pro-inflammatory Pathways

Diabetic nephropathy (DN) is a leading cause of ESRD worldwide, but its molecular pathogenesis is not well-defined and there are no specific treatments. In humans, there is a strong genetic component determining susceptibility to DN. However, specific genes controlling DN susceptibility in humans have not been identified. Here we describe a new mouse model, combining type 1 diabetes with activation of the renin angiotensin system (RAS), which develops robust kidney disease with features resembling human DN: heavy albuminuria, hypertension and glomerulosclerosis. Additionally, there is a powerful effect of genetic background regulating susceptibility to nephropathy. The 129 strain is susceptible to kidney disease, whereas the C57BL/6 strain is resistant. To examine the molecular basis of this differential susceptibility, we analyzed the glomerular transcriptome of young mice with albuminuria but without detectable alterations in glomerular structure . We find dramatic difference in regulation of immune and inflammatory pathways with up-regulation of pro-inflammatory pathways in the susceptible (129) strain and coordinate down-regulation in the resistant (C57BL/6) strain, compared to their respective baselines. Many of these pathways were also up-regulated in a rat model and in humans with DN. Our studies suggest that genes controlling inflammatory responses, triggered by hyperglycemia and hypertension, may be critical early determinants of susceptibility to DN.

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